Songwriting skills and musicianship. He actually wasn't a terrible drumline writer, just used a very simple kit to make very simple beats that went along with the catchy Beatles songs. I'm willing to bet if you stuck him in any other band, we would never have heard of him, whereas all the other Beatles probably would've made it anyway. Granted the connection and fluidity with the band as a whole I don't think would've been the same without ringo, I still feel like was the kid brother in the situation.
He stood out in "Rory Storm and the Hurricanes." The other Beatles would talk about how he came to be in the band. One time Pete Best couldn't make a show and Ringo stood in. Paul, John and George all looked at each other in amazement because of how well he fit in each song. With songwriting like that, all a drummer can do is fuck it up. He enhanced them. I'm a fan. There was a funny article a while back from a guy that hates Paul. He asserted that the Beatles are dying in reverse order of talent. He finished with, "if I were Ringo, I'd be scared."
Lol about the article. I think he fit the Beatles songwriting style for sure. Great chemistry with the band. He just my least favorite of the bunch. As I stated before, it's an unpopular opinion which can be risky to post because of peoples attachment to the Beatles. Not all of their songs were good, I would lean towards saying more of them are bad/mediocre, than good/epic. To clarify, I love the Beatles, they had some amazing songs, i just feel like they(especially ringo) get put on this pedestal when they were just a band that wrote good and bad songs. They made a ton of music, so it's hard to be all one way or the other. Also I feel like their strongpoint was songwriting, not musicianship. Especially In the beginning, they barely knew how to play their instruments.